This chapter focuses on the estimation and interpretation of gravity equations for bilateral trade. This necessarily involves a careful consideration of the theoretical underpinnings since it has become clear that naive approaches to estimation lead to biased and frequently misinterpreted results. There are now several theory-consistent estimation methods and we argue against sole reliance on any one method and instead advocate a toolkit approach. One estimator may be preferred for certain types of data or research questions but more often the methods should be used in concert to establish robustness. In recent years, estimation has become just a first step before a deeper analysis of the implications of the results, notably in terms of welfare. We try to facilitate diffusion of best-practice methods by illustrating their application in a step-by-step cookbook mode of exposition.

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Gravity Equations: Workhorse,Toolkit, and Cookbook

Life history biology sits on the interface between genetics and ecology, and both have made important theoretical and empirical contributions to our understanding. However, the connections between the disciplines have not always been as close as they might have been and this book takes some useful steps towards remedying this. It gives an excellent review of life history theory, and integrates this well with results from the empirical literature. After an 11-page introduction, Roff sets out ‘a framework for analysis’ in which he covers the necessary elements of quantitative and population genetics. This includes clear definitions of fitness in a range of circumstances, from density independent populations in constant environments through to the more complex situations of density and frequency dependence and environments that are spatially or temporally stochastic. Trade-offs are then examined, including a valuable analysis of potential pitfalls in studying them and ways that these can be avoided. The author then deals in turn with evolution in constant environments; stochastic environments and ‘predictable environments’. The last of these covers situations where there is environmental variation, but at least some information is available to allow individuals to make an adaptive response. The final chapter identifies 20 topics for future study. Some will find the book too dominated by theory. Others (but probably not readers of Heredity!) will find it contains too much genetics. But Roff does an excellent job of making the theory accessible, covering the essential issues and pointing to original sources for the details. Theory is related to a significant number of empirical studies, although there is room for another book reviewing the empirical literature on life histories in detail, and Roff’s book would provide a robust skeleton on which to hang this. To make my own assessment, I examined in detail Roff’s discussion of the question of fitness measures for density dependent populations in stochastic environments – an area in which I have been involved. I could not fault him – all the key references were there and the issues were made very clear without the more esoteric mathematics. I also examined some areas that I was less familiar with, and again the text was clear and easy to read. My only real criticism of the book would be that its very long chapters (more than 130 pages in one case) makes it difficult to find things. It would have been simple to address this by including the section headings on the contents pages. A minor personal quibble would be that the book usually expresses problems in terms of the intrinsic rate of increase, r, and the characteristic (Lotka) equation. A matrix formulation is often more tractable and is easier to generalise to density dependent populations and stochastic environments, so expanding on the relationship between the two would have been useful. But overall this is an excellent book. It brings together the key theory in a single place. It gives an invaluable route into the literature, with a bibliography of 1600 or so items. These features, and its identification of topics that need further study should make an important contribution to moving the field forward.

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Life History Evolution

We study the collapse of international trade flows during the global financial crisis using detailed data on monthly US imports. We show that credit conditions were an important channel through which the crisis affected trade volumes, by exploiting the variation in the cost of capital across countries and over time, as well as the variation in financial vulnerability across sectors. Countries with higher interbank rates and thus tighter credit markets exported less to the US during the peak of the crisis. This effect was especially pronounced in sectors that require extensive external financing, have limited access to trade credit, or have few collateralizable assets. Exports of financially vulnerable industries were thus more sensitive to the cost of external capital than exports of less vulnerable industries, and this sensitivity rose during the financial crisis. The quantitative implications of our estimates for trade volumes highlight the large real effects of financial crises and the potential gains from policy intervention.

https://papers.ssrn.com/sol3/Delivery.cfm/SSRN_ID1762701_code362537.pdf?abstractid=1502911&mirid=1&type=2

Off the Cliff and Back? Credit Conditions and International Trade During the Global Financial Crisis

ธรรมาภบาลของภาครฐเปนหนงในปจจยสำคญทสงอทธพลตอการพฒนาเศรษฐกจและสงคมของประเทศ บทความเรองนไดทำการพจารณาธรรมาภบาลของภาครฐใน 213 ประเทศทวโลก ซงแบงออกเปน 6 มต ไดแก การควบคมการคอรปชนความมประสทธผลของภาครฐ การปราศจากความรนแรงและการกอการรายคณภาพในการควบคม การบงคบใชกฎหมาย และเสรภาพของประชาชนในการแสดงความคดเหน ซงทำการศกษาโดยธนาคารโลกภายใตโครงการ Worldwide Governance Indicators จากการพจารณาพบวาประเทศทพฒนาแลวมธรรมาภบาลของ ภาครฐสงกวาประเทศกำลงพฒนาเปนอยางมาก สะทอนใหเหนวา ธรรมาภบาลของภาครฐคอหนงในปจจยทชวยขบเคลอนการพฒนาเศรษฐกจและสงคมของประเทศนอกจากนยงพบวาประเทศไทยยงไมสามารถพงพอใจกบระดบของธรรมาภบาลของประเทศในปจจบนได เนองจากยงอยในระดบคอนขางตา Government Governance: An Implication from Worldwide Governance Indicators Government governance is one of the major determinants of the economic and social development of the nations. This article reviewed government governance of 213 countries worldwide which was categorized into six dimensions, including control of corruption, government effectiveness, political stability and absence of violence/terrorism, regulatory quality, rule of law and voice and accountability, based on the study of the World Bank under Worldwide Governance Indicators project. After the revision, it was found that developed countries had far higher government governance than developing countries, implying that government governance is one of the factors which drive the economic and social development of the nations. Moreover, Thailand could not yet be satisfied with its current government governance since its rank was quite low.

ธรรมาภิบาลของภาครัฐ: นัยจาก Worldwide Governance Indicators

Volatility and growth: Credit constraints and the composition of investment

This paper analyzes the heterogenous reaction of exporters to exchange rate changes using a very rich French rm-level dataset with destination-specic export values and volumes on the period 19952005. We nd that high-performance rms react to a depreciation by increasing signicantly more their markup and by increasing less their export volume. This heterogeneity in pricing to market is robust to dierent measures of performance, samples and econometric specications. It is consistent with models where demand elasticity decreases with rm performance. Since aggregate exports are concentrated on high productivity rms, precisely those that absorb more exchange rate movements in

How do Different Exporters React to Exchange Rate Changes

We use a French firm-level data set containing 13,000 firms over the period 1994-2004 to analyze the relationship between credit constraints and firms' RD (ii) this result is only observed for firms in sectors that depend more heavily upon external finance, or that are characterized by a low degree of asset tangibility; (iii) in more credit-constrained firms, R&D investment plummets during recessions but does not increase proportionally during upturns.

/pdf/credit-constraints-and-the-cyclicality-of-r-d-investment-47dnccj1rt.pdf

Credit Constraints and the Cyclicality of R&D Investment: Evidence from France

https://halshs.archives-ouvertes.fr/halshs-00321632/document

Financial factors and the margins of trade: Evidence from cross-country firm-level data

This paper studies empirically the impact of mining on conflicts in Africa. Using novel data, we combine geo-referenced information over the 1997-2010 period on the location and characteristics of violent events and mining extraction of 27 minerals. Working with a grid covering all African countries at a spatial resolution of 0.5 0.5 degree, we find a sizeable impact of mining activity on the probability/intensity of conflict at the local level. This is both true for low-level violence (riots, protests), as well as for organized violence (battles). Our main identication strategy exploits exogenous variations in the minerals' world prices; however the results are robust to various alternative strategies, both in the cross-section and panel dimensions. Our estimates suggest that the historical rise in mineral prices observed over the period has contributed to up to 21 percent of the average country-level violence in Africa. The second part of the paper investigates whether minerals, by increasing the financial capacities of fighting groups, contribute to diffuse violence over time and space, therefore affecting the intensity and duration of wars. We find direct evidence that the appropriation of a mining area by a group increases the probability that this group perpetrates future violence elsewhere. This is consistent with feasibility theories of conflict. We also find that secessionist insurgencies are more likely in mining areas, which is in line with recent theories of secessionist conflict.

https://www.aeaweb.org/articles/pdf/doi/10.1257/aer.20150774

This Mine Is Mine! How Minerals Fuel Conflicts in Africa

This paper studies empirically the impact of mining on conflicts in Africa. Using novel data, we combine geo-referenced information over the 1997-2010 period on the location and characteristics of violent events and mining extraction of 27 minerals. Working with a grid covering all African countries at a spatial resolution of 0.5x0.5 degree, we find a sizeable impact of mining activity on the probability/intensity of conflict at the local level. This is both true for low-level violence (riots, protests), as well as for organized violence (battles). Our main identification strategy exploits exogenous variations in the minerals' world prices; however the results are robust to various alternative strategies, both in the cross-section and panel dimensions. Our estimates suggest that the historical rise in mineral prices observed over the period has contributed to up to 21 percent of the average country-level violence in Africa. The second part of the paper investigates whether minerals, by increasing the financial capacities of fighting groups, contribute to diffuse violence over time and space, therefore affecting the intensity and duration of wars. We find direct evidence that the appropriation of a mining area by a group increases the probability that this group perpetrates future violence elsewhere. This is consistent with "feasibility" theories of conflict. We also find that secessionist insurgencies are more likely in mining areas, which is in line with recent theories of secessionist conflict.

https://papers.ssrn.com/sol3/Delivery.cfm/SSRN_ID2627073_code459177.pdf?abstractid=2627073&mirid=1

Nicolas Berman

Papers

How do Different Exporters React to Exchange Rate Changes

Credit Constraints and the Cyclicality of R&D Investment: Evidence from France

Financial factors and the margins of trade: Evidence from cross-country firm-level data

This Mine Is Mine! How Minerals Fuel Conflicts in Africa

This Mine is Mine! How Minerals Fuel Conflicts in Africa